1. Field of the Invention
The present invention relates to an antenna system and a wireless device, and more particularly, to an antenna system and a wireless device capable of enhancing isolation between two sets of antennas effectively.
2. Description of the Prior Art
As the wireless communication technology evolves, the demand for wireless networks increases. In the next generation, a standard of IEEE 802.11ac, exploiting multi-user multiple input multiple output (MU-MIMO) technology to enhance transmission rate, is widely adopted by the industry for communication products in wireless local area network (WEAN).
For wireless devices in a WLAN such as wireless routers, wireless base stations, wireless access points, etc., in addition to a plurality of antennas, more than one radio card (usually two radio cards) is required for providing a higher data transmission rate and better quality of service (QoS). That is, a first set of antennas is coupled to a first radio card and a second set of antennas is coupled to a second radio card. However, when all of the antennas operate at a same frequency band, the first set of antennas coupled to the first radio card and the second set of antennas coupled to the second radio card cause mutual interference, which reduces an isolation between the first set of antennas of the first radio card and the second set of antennas of the second radio card, reduces the data transmission rate of the wireless device, and degrades the QoS of the wireless device.
Therefore, how to enhancing isolation between two sets of antennas is a significant objective in the field.